D2D communication refers to a radio technology which enables a plurality of devices (for example, a plurality of terminals) to exchange voice, data, and so on directly with each other without involving a base station. D2D communication includes UE-to-UE communication and peer-to-peer communication. Also, D2D communication can be applied to Machine-to-Machine (M2M) communication, Machine Type Communication (MTC), and others.
D2D communication is being considered as one of solutions that can relieve the burden of a base station due to rapidly growing data traffic. For example, different from existing wireless communication systems, D2D communication enables devices to communicate data directly with each other without employing a base station, thereby reducing overload on a network.
Also, D2D communication provides advantageous effects such as simplification of a procedure in a base station, reduction of power consumption for devices participating in D2D communication, increase of data transmission speed, extension of network capacity, distribution of communication load, and extension of cell coverage.